This invention relates to a planetary drive assembly and, more particularly, to a planetary wheel drive assembly which permits the ground-engaging wheel to be disconnected from the power train so that the wheel may be free-wheeling for travel at highway speeds without driving the gears which are part of the power train to the wheel.
Industrial, off-road and agricultural equipment include individually powered high torque wheels so that the wheels are provided with smooth, infinitely variable power for both forward and reverse operations and for supplying power to individual wheels according to need. Typically, these vehicles include a hydraulic motor for each wheel, although the power source may be pneumatic, electric or mechanical. Rotational power is supplied to each wheel through a planetary gear train which may be connected or disconnected from the power source.
Prior art arrangements for engaging and disengaging a powered wheel from its source include arrangements which are set forth in U.S. Pat. Nos. 3,459,070; 4,453,852; and 4,692,049. In U.S. Pat. No. 3,459,070, there is disclosed a wheel drive mechanism which includes a drive shaft and a sun gear which drives a driving wheel through a planetary gear set. In order to facilitate towing of the vehicle, an access cover is provided which may be removed for removal of the driving sun gear. While the removal of the sun gear disconnects the gear train from the drive shaft, the gear train is rotated by the towing action. Thus, the vehicle may only be towed at low speeds since high speed towing would cause the gears to churn the oil to such a degree that dangerous heat levels would be attained in the gear train. U.S. Pat. Nos. 4,453,852 and 4,692,049 are improvements in the arrangement disclosed in U.S. Pat. No. 3,459,070, in that these patents disclose mechanisms to disengage the sun gear from the drive shaft by quick disconnect mechanisms. Since the gear train is still associated with the ground-engaging wheel, oil churning during towing is still a problem.